SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4e822680dec2ced2cefe8e8437883bb78bb3ec8c6799307b2dc0408a109fbc6' 
  AND token = 'is/PNK/zZIOoNiyPoqqEMemeKrIHZpiYzafyiT+BM+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}